Prospective Assessment of the Association Between Circulating Tumor Cells and Control of Brain Disease After Focal Radiation Therapy of Breast Cancer Brain Metastases

Abstract

Prospective assessment of the association between circulating tumor cells and control of brain disease after focal radiotherapy of breast cancer brain metastases, Advances in Radiation Oncology (2021), doi:

Heterogeneity of HER2 Expression in Circulating Tumor Cells of Patients with Breast Cancer Brain Metastases and Impact on Brain Disease Control

“…Detailed descriptions of the SRT procedure and the follow-up MRI imaging have already been published [6,12]. Briefly, all participants were treated within 1 week after the MRI and computed tomography (CT) imaging for the SRT planning by a linear accelerator with micromultileaf collimator, cone beam CT, and robotic couch.…”

“…Recently, a prospective study showed that the number of circulating tumor cells (CTC) may have a role as a biomarker of early DBF and a guide for salvage therapy after initial stereotactic radiotherapy/radiosurgery (SRT) [6]. In addition to the number, the phenotype of the CTC was evaluated in the same study, including the expression of human epidermal growth factor receptor 2 (HER2), along with other potential markers for the identification and characterization of CTC for breast cancer brain metastases [7,8].…”

Clinical Biomarkers for Early Identification of Patients with Intracranial Metastatic Disease

“…Circulating tumor cells disseminated by primary or metastatic lesions have been identified in the peripheral blood of patients with IMD secondary to breast cancer, NSCLC, and melanoma [ 33 , 35 , 36 , 37 , 38 ]. Current research efforts have focused on the detection of CTCs as prognostic markers.…”

“…First, detection of CTCs is highly dependent on the method employed. Guedes de Casto et al, for example, were able to detect CTCs in 39/39 patients with melanoma before SRS using a method based on isolation by filtration [ 36 ]. By contrast, the majority of studies employ the CellSearch System (Veridex, Warren, NJ, USA), which relies on immunomagnetic isolation and separation of cells based on epithelial makers, and report CTC positivity rates in smaller proportions in cancer patients (ranging from 13% to 49% of patients being CTC positive) [ 32 , 33 , 34 , 35 ].…”

“…By contrast, the majority of studies employ the CellSearch System (Veridex, Warren, NJ, USA), which relies on immunomagnetic isolation and separation of cells based on epithelial makers, and report CTC positivity rates in smaller proportions in cancer patients (ranging from 13% to 49% of patients being CTC positive) [ 32 , 33 , 34 , 35 ]. Second, detection of CTCs in peripheral blood is not specific to IMD, and, furthermore, detection rates can be lower in patients with IMD compared to other metastatic sites due to the lack of identifiable epithelial surface markers for isolation [ 36 , 56 ]. Hanssen et al, for example, reported even lower CTC positivity rates in patients with oligometastatic IMD based on a cut-off of ≥ 2 CTCs per 7.5 mL of blood ( n = 34, 5.9% CTC positive) [ 33 ].…”